Unit 9 Flashcards

1
Q

What is continental crust

A

Layers of igneous, sedimentary and metamorphic rocks, that form, geological continents, a.k.a. landmass and their continental shelves

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2
Q

Oceanic crust

A

The layer of igneous rock that forms at the base of the ocean floor

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3
Q

Mantle

A

Layer of silicate rock between the rigid crust and the outer core. It’s made up of several layers that are all ultramafic (low silica)

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4
Q

Core

A

Outer core liquid inner core solid due to intense pressure, 95% iron 5% nickel

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5
Q

What is seismology?

A

The study of vibrations on and within the earth or seismic waves.

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6
Q

What are surface waves?

A

These radiate along our surface, and they form when a body wave reaches the surface

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7
Q

What are body waves?

A

These propagate through earth, and their most useful for understanding our interior. Usually all waves are caused by earthquakes including surface waves.

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8
Q

What is a compression wave or P wave?

A

These are compression waves they’re like a slinky material compresses as the wave moves past it, and they are the first wave to be detected

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9
Q

What are sheer waves?

A

These arrive after the pew waves material, vibrates as the wave moves past and it looks like a hair curl very loose

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10
Q

What are the two body waves?

A

P Aves waves or compression waves, and S waves, which are known as sheer waves

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11
Q

How are body waves affected by the state of the rock

A

We velocities increase with density, so compression waves are slow down in liquid medium, where sheer waves cannot travel through liquid. Usually this means S waves can’t go through the core.

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12
Q

What is the shadow zone?

A

Essentially where the S waves could not go through the core and what areas were not hit

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13
Q

How does internal temperature change with depth?

A

Temperature increases with depth

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14
Q

What is mantle convection

A

Heat from the core is being brought towards the surface faster so it’s heating the lower mantle material near the source gets hot, which expands and rises think of boiling water. Convection is the outer core trying to reverse the magnetic field.

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15
Q

What is responsible for earth magnetic field

A

He is transferred from the solid, inner core to the liquid, outer core and the convection of liquid iron in the outer, core, conducts, electricity, and its motion generates a magnetic field

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16
Q

What does isostacy

A

This is the rising or settling of a portion of earths solid crust that occurs when weight is removed or added, maintaining equilibrium between buoyant forces by pushing the crust up and gravity, pulling it down

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17
Q

Isostatic vs nonisostatic

A

Heavier matter will sink deeper vs matter not sinking at all

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18
Q

What is continental drift?

A

The theory that earths continents have moved over geological time relative to each other, appears as if they have drifted across the ocean

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19
Q

Palaeomagnetism

A

Earths magnetic field, magnetic field behaves, as if there was one giant magnet at the core. When magnetic materials, cool, they become digitized parallel to earth magnetic field at the time, so they retain remanent magnetism.

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20
Q

What is inclination and declination regarding earths magnetic field?

A

Inclination is the steepness/the ankle and declination is the direction 

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21
Q

Remnant magnetism

A

The inclination and declination of the magnetic field can tell you the orientation and latitude at which the deposit was formed. This is how we track migration of continents around the globe.

22
Q

Why is remnant magnetism of the ocean floor striped?

A

New ocean floors, hypothesize to form at sea floor, spreading bridges, a.k.a. mid ocean ridges, so it pushes older sea floor away on either side, which creates a mirror

23
Q

Plate tectonics

A

The theory that explains how major landforms are created as a result of earths mantle convection. Plates are constantly moving in different directions.

24
Q

Divergent plate, boundaries

A

Plates are moving away from each other

25
Q

Convergent plate, boundaries

A

Plates are moving towards each other

26
Q

Transform plate boundaries

A

Plates are moving against each other

27
Q

Mid ocean ridges

A

Two lithospheric plates are moving away from each other so divergent. This creates basalt deposits, which are mafic extrusive rocks. These are generating new seafloor.

28
Q

Ocean to ocean plate boundaries

A

Two plates of oceanic crust push against each other. This oceanic crust is thin and dense so one played will subduct beneath the other. Usually the older/colder/denser plate will sink. Water is released during subduction, which leads to flux melting. A buoyant magma moves towards the service to create a chain of volcanic islands.

29
Q

Oceanic to continent plate, boundaries

A

Oceanic crust is pushing against continental crust, the oceanic plate will subduct because it is denser than continental crust. The continental crust crumbles up or thickens, which creates the mountain. The melting of this oceanic plate leads to magma plumes, that result in composition volcanoes.

30
Q

Continent continent plate, boundaries

A

Continental crust, colliding with another continental crust. Both plates are buoyant, or felt sick, so neither will subduct no volcanos form, because no melting of material subducted into the mantle, a thick crumbles zone develops, which creates large mountains

31
Q

Transform plate boundaries

A

One plate slides past another plate without production or destruction of crystal material usually their ocean to ocean boundaries

32
Q

What is stress and what does it lead to?

A

Rocks are subjected to stress due to movement of plates and burial (weight of overlying rocks,) it leads to strain(change in shape or size) which is a rock response to stress

33
Q

How is stress applied if it’s due to just burial

A

Stress will be equal in all directions

34
Q

How will stress be applied if it’s due to burial and tectonic forces

A

Stress will be unevenly distributed in all directions

35
Q

Elastic deformation

A

This is reversible. Once this stress is removed, the rock returns to its original state.

36
Q

Plastic deformation

A

Rocks will deform under stress without breaking, essentially bending, and this is permanent

37
Q

Brittle deformation

A

Permanent and rocks will break or fracture under. Applied stress.

38
Q

What are the two different folds?

A

Syncline, which is U-shaped and the youngest rock are in the middle, and anticline, which is end shaped and the oldest rock are in the middle

39
Q

What are the parts of a fold?

A

Fold access or the hinge line this is the line that runs along the nose of the fold or along the bend. Then we have the axle plane which is an imaginary plane that contains the hinge and then the limbs which are the arms of the fold that bend away from the axle plane if it’s anticline or towards the axle plane if it’s syncline

40
Q

What happens if the hinge line is at an angle on the fold?

A

It will create something called, plunging folds, and the surface trace of the rocks look like arches

41
Q

Plunging anticline

A

Hinge line is at an angle to the land surface rock show a u-shape

42
Q

Plunging syncline

A

Looking at it head on you see the newest rock and the in circles around it you see the older rocks

43
Q

Faults

A

Result of brittle deformation, where rock breaks in response to applied stress

44
Q

Fault, trace

A

Expression of the fault on the land service basically just looking at the fault head on

45
Q

Hanging wall

A

This is a block above the fault

46
Q

Footwall

A

Block below the fault

47
Q

Normal fault

A

The hanging wall drops down and the foot wall moves up

48
Q

Reverse fault

A

The hanging wall slides up along the football. This usually occurs in area of compressional stress

49
Q

Strike slip fault

A

Steep or vertical faults, where the rock has been moved, horizontally relative to each other, there is no vertical displacement

50
Q

Strike slip fault

A

Steep or vertical faults where the rock has moved horizontally from each other no vertical displacement